Beryllium aluminum alloy



- No Drawing.

Patented Apr. 25, 1933 UNITED STATES PATENT" OFFICE JOSEPH -KENT SMITH, OF DETROIT, MICHIGAN, A SSIGNOR TO BEERYLLIUM DEVELOP- MENT CORPORATION; OF N EW YORK, N. Y., A CORPORATION" OF DELAWARE BERYLLIUM ALUMINUM ALLOY This invention relates to alloys characterized byextreme lightness and great strength,

therefore does not lend itself readily to rolling, forging, or those other mechanical operations necessary to bring metals into readily usable forms, especially those forms used where extreme lightness is required, it has been found necessary to alloy beryllium with smaller quantities of aluminum so as to obtain an ultra-light metallic material possessing those characteristics which will permit of the mechanical operations cited. The roportions of aluminum added to the berylhum will vary in quantity with the requirements of the situation, the lower the quantity of aluminum added, the lighter the resulting alloy, but the greater the difliculties of mechanical manipulation. When the aluminum content of the alloy is as little as ten percentof the total, great precautions are necessary in rolling or forging the alloy, while the alloy' with thirty percent of alum num, with a specific gravity of approximately 2.0, lends itself quite readily to all the usual mechanical operations. Alloys of about equal parts of beryllium and aluminum are still easier to work, but they lack the greater strength and superior lightness of the alloys lower in aluminum. The alloy approximating seventy percent beryllium and thirty percent aluminum represents best current practice in this series, presenting a nice balance between the various factors involved.

However, the simple binary beryllium-' aluminum alloys, despite their greater strength as compared with pure aluminum,

leave still something to be desired in the matter of strength, machinability, etc. I have found, in my invention, that by adding, to any of the beryllium-aluminum alloy series in which beryllium predominates-from about to about 7 0% with aluminum from about 25% to about 40 %small quantities of manganese and vanadium, with or without simultaneous additions of small quantities Application filed Deceinber 22,1931. Serial No. 582,653.

of molybdenum, significant increases in strength, flmachinability, etc. can be efiected, without any material increase in the specific gravity of the alloy. The heavy metals mentioned as addition agents should never exceed five percent of the total weight of the alloy, and, in the preferred compositions, thesia metals do not exceed two percent of the tota If desired, such alloys can be made by the addition of the requisite quantities of the free heavy metals to a molten berylliumaluminum alloy. A better method consists in melting the beryllium and aluminum together, employing as a flux a mixture of the chlorides and fluorides of calcium with some cryolite. To this the vanadium (and, if desired, the molybdenum) is added in the form of compounds readily. reducible in the circumstances, like calcium vanadate (and calcium molybdate). Under the conditions, elementary vanadium (and molybdenum) is formed by reduction and enters into the alloy. The manganese is added by means of a cleansing alloy, comprising aluminum, magnesium and, manganese. The magnesium almost all boils, out readily, while the manganese and aluminum unite with the primary alloy, resulting in the final multi-constituent alloy.

As compared with the simple binary beryllium-aluminum i alloy of seventy per- "cent beryllium content, a similar alloy contaim'ng about one-half percent each of vanadium, molybdenum and manganese is more readily workable, flows better, casts better, has greater strengthand resistance to' The presence of the heavy metals hardens I the aluminum eutectic, giving. the multiconstituent alloy a relatively low coeflicient of friction; the alloy is therefore useful for piston rings, pistons, and similar moving parts involving frictional efiects. a

In cast form, alloys covered by this invention have tensile strengths ranging from thirty thousand to fifty thousand pounds per square inch.

The percentages are by weight.

I claim 1. A beryllium-aluminum alloy of approximately the following composition: beryllium from 55% to 70%, aluminum from to 40%, and manganese molybdenum and vanadium each. v

2. A beryllium-aluminum alloy of approximately the following composition:

beryllium from 55% .to aluminum from 25% to 40%, and manganese, vanadium and molybdenum from about to 2%'% each but not materially in excess of i I 5% in the aggregate.

In testimony whereof I have hereuntl signed my name.

JOSEPH KENT SMITH.

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